Conceptualising long-term monitoring to capture environmental, agricultural and socio-economic impacts of the Mzimvubu water project in the Tsitsa River

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The Mzimvubu River is the largest undeveloped river in South Africa despite having high annual runoff, high environmental status, high tourism potential, and being suitable for afforestation and moderately suitable for dryland/rainfed and irrigation agriculture. For these reasons, the Department of Water Affairs (DWA) investigated the potential of building a multipurpose dam in the Mzimvubu basin to serve as a catalyst for economic and social development. After several feasibility studies on potential sites, the Ntabelanga site in the Tsitsa river was chosen as the most appropriate site for the multipurpose dam. Another smaller dam site was identified downstream of Ntabelanga for the hydropower generation.
Globally, large dams are vital development infrastructure that can society to meet various needs. These needs include water for domestic and industrial use, agricultural irrigation, and hydro-electric power. Dams can also help to “reduce peak discharge of flood water” and “increase the depth of water in a river so as to improve navigation”. Agricultural rejuvenation and job creation are the main drivers behind the conceptualisation of the Ntabelanga dam.
Despite the widely acknowledged benefits of large dams, dam development continues to come up against important questions of social and environmental sustainability. The success and sustainability of a dam project is no longer just a matter of it's ‘technologically feasibility’ or driver of ‘economic development', it is equally an important sociological matter. Success is increasingly being measured by the extent to which the project coheres with specific social and environmental dynamics in the local area–in the short-, medium- and long-term.
There is also the crucial question of environmental impact, and the construction of dams has a direct impact on the environment through permanent inundation of previously dry areas, alteration of stream flow regimes (reduction in natural flooding), and fragmentation of river ecosystems, thereby reducing species diversity in almost all cases. Indirectly, land-use change associated with dam constructions can significantly alter the equilibrium of ecosystems. These changes, generally, can lead to more intensive land utilisation, and these impacts add to the controversies around large dam projects Frequently, scientific studies associated with dam construction focus more on finding out the most technically feasible place to build it, than on the long-term socio-environmental issues that come in its train.
This research, therefore, proposes a procedure for long term monitoring of environmental, agricultural and socio-economic changes associated with the building of the Ntabelanga dam. The current situation in the Ntabelanga area is first described with the focus on the physical environment (climate, streamflow, soils and environmental sensitive areas), the dominant agricultural practices as well as the perspectives, hopes and fears of communities in the study area. The report suggests a long term monitoring regime and methodologies that should be followed to capture the impact of the dam (before, during and after construction) on the environment, agriculture and people.akpan